ESTRO 38 Abstract book

S315 ESTRO 38

Medicine, Sydney, Australia ; 3 Ingham Institute of Medical Research, Liverpool Hospital, Sydney, Australia Purpose or Objective Optimal radiotherapy utilisation rates suggest that approximately 48% of patients should receive radiotherapy based on evidence-based guideline recommendations and that 44% of cancer patients should receive radiotherapy within their first year of diagnosis (1). It has been widely reported that actual rates are often significantly lower than optimal. The aim in this study was to estimate the local control and overall survival shortfall that occurs as a result of radiotherapy under-use and to identify factors that predict under-use in NSW. Material and Methods All cases of registered cancer diagnosed in NSW, Australia, between 2009-2011 were identified from the NSW Cancer Registry and linked with data from all public and private radiation oncology departments. The actual Radiation Therapy utilisation (RTU) rate was calculated and compared with published evidence-based optimal rates (1). The deficit in radiotherapy use for each evidence- based radiotherapy indication was used to estimate the impact on 5-year local control (LC) and overall survival (OS). These were compared to the published estimates of radiotherapy benefits in the setting of optimal use (2). OS and LC shortfall in person number - defined as the number of people not achieving LC and OS benefit due to RT underutilisation - was then calculated. Univariate and multivariate analyses were performed to identify factors that contributed to reduced RTU. Results 110 645 patients were diagnosed with cancer in NSW during the study period. The overall RTU rate was 25% within the first year of diagnosis compared to the reported optimal rate of 44% within the first year of diagnosis (2). The 5-year OS shortfall was 2.2% and 5-year LC shortfall was 10.9%.It is estimated that 1757 and 361 patients per year not receiving radiotherapy in NSW had local failure and poorer survival respectively during this study period. Male gender, older age, localised disease and longer travel distance were factors predicting radiotherapy under- utilisation on multivariate analysis. When compared with our analysis of NSW data from 2004, the current study shows an estimated overall survival improvement of 9% (3). Conclusion Under-use of recommended radiotherapy for cancer has been identified in this study, with a negative impact on patient outcomes. While improving, further work needs to be done to reduce this shortfall further. Older age, male gender and longer travel distance were predictors for sub- optimal RTU. These findings would assist in health service planning for radiotherapy and call for better adherence to treatment guidelines. Identification of the specific evidence-based indications with the greatest shortfall would assist with prioritising strategies to address the gap. References: 1. Barton MB, et al. Radiotherapy and oncology. 2014;112(1):140-4. 2. Hanna TP, et al. Radiotherapy and oncology 2018;126(2):191-7. 3. Batumalai V., et al.. Radiotherapy and oncology 2018 (in press). OC-0600 Assessment of non-adherence to external radiotherapy treatment in cancer patients in Catalonia,Spain J.M. Borras 1 , R. Font 2 , J. Solà 2 , M. Macià 3 , M. Arenas 4 , R. Verges 5 , A. Eraso 6 , V. Tuset 6 , A. Biete 7 , J.M. Solé 8 , N. Farré 9 , A. Pedro 10 , M. Mira 11 , J.A. Espinàs 2 1 University of Barcelona, Clinical Sciences, Catalonia, Spain; 2 IDIBELL, Pla Director d'Oncologia, Catalonia, Spain; 3 Catalan Institute of Oncology, Catalan Institute of Oncology, Catalonia, Spain ; 4 Hospital Sant Joan de

Reus, Hospital Sant Joan de Reus, Catalonia, Spain ; 5 Hospital Universitari de la Vall d'Hebron, Hospital Universitari de la Vall d'Hebron, Catalonia, Spain ; 6 Institut Català d'Oncologia, Institut Català d'Oncologia, Catalonia, Spain; 7 Hospital Clínic de Barcelona, Hospital Clínic de Barcelona, Catalonia, Spain ; 8 Consorci Sanitari de Terrassa, Consorci Sanitari de Terrassa, Catalonia, Spain; 9 Hospital de la Santa Creu i Sant Pau, Hospital de la Santa Creu i Sant Pau, Catalonia, Spain ; 10 Hospital Clínica Plató, Hospital Clínica Plató, Catalonia, Spain ; 11 Hospital Arnau de Vilanova, Hospital Arnau de Vilanova, Catalonia, Spain Purpose or Objective Non-adherence to external radiotherapy is an aspect of treatment which has not been fully explored. The objective of this study is to analyse the relevance of this problem and its impact on 1-year survival Material and Methods A Cohort study design was carried out with a prospective follow-up of cancer patients with indication of external radiotherapy. All patients with indication of treatment during year 2016 in the hospital of the public sector in Catalonia were included. Adherence was deemed acceptable if total dose received was over 90% of the dose prescribed. Statistical analysis was performed according to type of tumour, intention of treatment and age. Logistic regression was carried out to assess factors associated to adherence and Cox analysis was applied to assess their relationship with survival Results In total, 15.157 patients were included with an average age of 64.6 (± 14.0); 51.3% were males. Most frequent tumours were breast (27.4%), lung (16,1%) and prostate (12.4%). Radical intent was indicated in 69.2% of cases and 18.7% of patients received concomitant chemo. At least one day interruption of treatment, excluding public holidays, was observed in 41.8% of cases. The reasons (multiple choice) for these interruptions were, 75.8% due to problems with the equipment, 17.9% for medical reason, 7.9% due to the patient preference and 20.9% for others reasons. Patient adherence was of 95.5% of patients (receiving more than 90% of total dose). Radical intent was related (OR: 3.11; IC: 95%: 2.6-3.7) to better adherence. Older age was associated with lower probability of adherence. Head and neck, lung, digestive other than rectal and bone (including metastasis) cancers were associated with lower probability of adherence; while breast and prostate cancer patients were associated with significantly higher than average adherence. One-year survival was signifycantly higher among adherent patients, both in radical (HR: 4.5; IC95%:3.8-5.4) and palliative (HR: 2.1; IC95%:1.8-2.4) intent Conclusion Adherence of treatment is very high among this cohort of population based patients receiving treatment in the public sector in Catalonia. Lack of adherence is related to lower probability of survival and this factor should be considered in the follow-up of patients with radiotherapy treatment OC-0601 Stereotactic body radiotherapy for oligometastatic disease in belgium: costs and budgetary impact D. Nevens 1 , I. Kindts 2 , N. Defourny 3 , M. Rosskamp 4 , C. Mercier 5 , H. De Schutter 4 , C. Van de Voorde 6 , Y. Lievens 7 1 Department of Radiation Oncology, Iridium Kankernetwerk, University of Antwerp ; 2 KU Leuven- University Hospitals Leuven, Lab of Experimental Radiation Oncology, Leuven, Belgium ; 3 ESTRO, European Society for Radiotherapy and Oncology, Brussels, Belgium; 4 BCR, Belgian Cancer Registry, Brussels, Belgium; 5 University of Antwerp, Molecular Imaging- Pathology- Radiotherapy & Oncology MIPRO, Antwerp, Belgium; 6 KCE, Belgian Health Care Knowledge Centre,